Regulating resistance.



G. EGLY.

REGULATING RESISTANCE.

APPLICATION mu; 050.5.1914.

Patnm May 28, 191%;

UNITED STATES PATEN T OFFICE.

GEORG- EGLY, OF BERLIN-TREPTOW, GERMANY, ASSIGNOR TO GEBR. SIEMENS & (30., 0F LICHTENBERG, NEAR BERLIN, GERMANY, A COPARTN'ERSHIP.

REGULATIN G RESISTANCE.

Specification of Letters Patent.

Patented May 28, 1918.

. Application filed December 5, 1914. Serial No. 875,694.

To all whom it may concern:

Be it known that I, Gnone EGLY', a German citizen, and resident of Berlin-Treptow, Germany, have invented certain new and useful Improvements in Regulating Resistances, of which the following is a specification.

My invention relates to a novel construction of regulating resistances employing as resistance body an artificially made resistance material, such as for instance described in the U. S. Patents No. 866344, dated September 17, 1907, and No. 1,012,531, dated December 19, 1911.

The regulating resistance according to my present invention comprises 111 brief a resistance body of the aforementioned kind having the shape of a segmental cog-wheel in which the cogs carry the contacts for the several resistance steps, and a lever which at one of its ends is pivoted at the center of said segmental cog-wheel and with its other end makes a sliding contact with said cogs, so that the current may be introduced at the center and taken ofl at one of the ends of the cog-wheel. In order to obtain a convenient form of the regulating resistance as a whole, the cog-wheel is preferably made of such segmental form that it will circumscribe almost a full circle, with only a suflicient distance between the ends of the segment. By this arrangement several advantages are attained. Firstly, on account of the cogwheel shape of the resistance body the contact elements will have a larger cooling surface and will therefore cool off better than if they are embedded in a resistance body with continuously increasing cross-section, and secondly the construction of the entire apparatus will become more compact as compared with a straight resistance body. Also in spite of the relatively smaller d1s tance between the contacts of the resistance body according to my invention a longer path for the current is obtained between a contact and the succeeding one, and the distribution of current in the resistance body and at the points of contact becomes better and more uniform than when the contacts are merely arranged one behind the other on an uninterrupted resistance body.

In the accompanying drawing Figure 1 shows an elevation, partly in section, Fig. 2 a top view, of a regulating resistance according to my invention, and Fig. 3 a modified form of the resistance body.

In the drawing a designates the resistance body of the shape of a segmental cog-wheel, b the cogs projecting therefrom, a the contact pieces which are carried by the cogs of the resistance body, (Z is the brush for taking off the current from the contacts, and e a lever or handle which is pivotally mounted at the center of the segmental cog-wheel for moving said brush (Z over the contacts of the cogs Z). It is especially advantageous to provide the cogs or contact places with metal pieces or caps which surround the several cogs of the resistance body from the outside. These metal pieces are designated by the letters 9 and f and may be so constructed that they will either extend from above and from below around the cog or they may be made integral with each other entirely around said cog. These metal surfaces on the one hand will improve the contact surface between the contact and the resistance body and on the other hand also impart a greater mechanical strength to the latter and especially a greater safety against breaking of the cogs.

A. modified formof the resistance body is shown in Fig. 3. Here the cross-section of the resistance body is made to increase from one end to the other end of the segmental cog-wheel, whereby the effect is obtained that for like distances 'of the contacts the resistance steps are made greater at the beginning than at the end of the switching period or vice versa, as desired. In the form of the resistance body as shown in Fig. 3 this increase in cross-section is attained by making the interior of the resistance body of the shape of a spiral and not of a circular form as in the construction shown in Fig. 2.

Having thus described my invention 1 claim as new and desire to secure by Letters Patent of the United States c 1. A regulating resistance comprising in combination, an approximately horse-shoe shaped resistance block, projections extending radially from the outer periphery of said block, metallic contact pieces disposed adjacent to the outer ends of said projections, and a centrally pivoted contact switch adapted to successively contact with all the contact pieces.

2. A regulating resistance comprising in combination, an approximately horse-shoe shaped resistance block of varying cross-section, projections extending radially from the outer periphery of said block, metallic contact pieces disposed adjacent to the outer ends of said projections, and a centrally pivoted contact switch adapted to successively contact with all the contact pieces.

3. A regulating resistance comprising in combination, an approximately horse-shoe shaped resistance block, projections extending radially from the outer periphery of said block, metallic contact pieces disposed adjacent to and partly inclosing the outer periphery of said projections, and a'centrally pivoted contact switch adapted to successively contact with all the contact pleces.

4:. A regulating resistance comprising in combination, an approximately horse-shoe shaped resistance block whose cross-section steadily increases from one end of the body to the other, projections extending radially from the outer periphery of said block, metallic contact pieces disposed adjacent to the outer ends of said projections, and a centrally pivoted contact switch vadapted to successively contact with all the contact pieces.

5. A regulating resistance comprising in combination, an approximately horse-shoe shaped resistance block of varying cross-section, projections extending radially from the outer periphery of said block, metallic contact pieces disposed adjacent to and partly inclosing the outer periphery of said projections and a centrally pivoted contact switch adapted to successively contact with all the contact pieces.

In testimony whereof I have hereunto set my signature in the presence of two subscribing witnesses.

GEORG EGLY.

Witnesses HENRY HASPER, WOLDEMAR HAUPT.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Eatents,

Washington, D. G. 

